The birth of fraternal twins is a characteristic frequently observed in callitrichids. Cytogenetic studies have demonstrated hematopoietic chimerism in marmosets with the occurrence of two cell lines 2n=46,XX/46,XY in females and males co-twins, without phenotypic changes. Amplification by PCR have also been used to verify the presence of the SRY gene in female chimaeras. Our aim was to verify ...

BACKGROUND We have previously reported operational tolerance in patients receiving human leukocyte antigen-mismatched combined kidney and bone marrow transplantation (CKBMT). We now report on transient multilineage hematopoietic chimerism and lymphocyte recovery in five patients receiving a modified CKBMT protocol and evidence for early donor-specific unresponsiveness in one of these patients. ...

Tacrolimus is a more potent and satisfactory immunosuppressant than CyA for combination therapy with prednisone. In randomized trials comparing the 2 drugs, the ability of tacrolimus to rescue intractably rejecting grafts on the competing CyA arm allowed equalization of patient and graft survival on both arms when the intent-to-treat analytic methodology was applied. The ability of tacrolimus t...

CONTEXT AND OBJECTIVE Non-myeloablative hematopoietic stem cell transplantation (NMA-HSCT) is performed in onco-hematological patients who cannot tolerate ablative conditioning because of older age or comorbidities. This approach does not completely eliminate host cells and initially results in mixed chimerism. Long-term persistence of mixed chimerism results in graft rejection and relapse. Inv...

Data on the application of donor lymphocyte infusions (DLIs) following reduced-intensity transplantation (RIT) remain limited. Persistence of host antigen-presenting cells might increase the efficacy or toxicity of cellular immunotherapies. We report the results of dose-escalating DLIs in 46 patients undergoing RIT, who received a total of 109 infusions to treat mixed chimerism or residual or p...

Mixed hematopoietic chimerism is a state in which bone marrow hematopoietic stem cells from two genetically different animals coexist. We investigated whether mixed hematopoietic chimerism, resulting from the transplantation of host and donor bone marrow into a lethally irradiated rat, would confer donor-specific tolerance to lung allografts. Recipient rats (Fisher or or Wistar Furth [WF]) were...

Incomplete donor chimerism (DC) after hematopoietic stem cell transplantation (HSCT) is associated with reduced overall and disease-free survival and decreasing DC can precede overt relapse of malignant diseases. Sensitive chimerism quantification may therefore allow for early therapeutic intervention, potentially improving treatment response. Frequently, post-HSCT chimerism monitoring involves...

Recent evidence suggests that the leukocytes (including stem cells) contained in organs migrate after transplantation and produce persistent chimerism, which is essential for sustained survival of the allografts (1, 2). With this information, we proposed as an encompassing principle that success after either clinical bone marrow or organ transplantation "(whether described as) tolerance or graf...

Recent evidence suggests that passenger leukocytes migrate after organ transplantation and produce persistent chimerism, which is essential for sustained survival of the allograft. Here, we describe how this hematolymphopoietic chimerism provides an important framework for interpretation of post-transplant phenomena and for initiation of therapeutically oriented transplantation research.

A case of monochorionic twin boys delivered at 34 weeks of gestation following induced ovulation with clomiphene is described. One twin was typed as blood group AB and the other as B. Flow cytometry showed blood group chimerism. DNA polymorphism analysis of peripheral lymphocytes and hair root cells showed that the chimerism was confined to the blood cells and they were dizygotic.